Hanging wallpaper is a good do-it-yourself project, but wallpapering corners to make them look perfect can be a challenge. Get great results on wallpapering inside and outside corners by following these tips for a professional finish.

Wallpapering inside corners

Never wrap wallpaper more than 1⁄2 inch around an inside corner with a drop. Even if the walls are perfectly plumb, the paper will pull away from the corner as it dries, making it vulnerable to tearing or wrinkling. Instead, make a wrap-and-overlap seam.

Use a wrap-and-overlap seam at inside (l.) and out-of plumb outside corners (r.).

Use a wrap-and-overlap seam for out-of-plumb outside corners, by following these steps:

As you reach the last strip before a corner, measure and cut the strip lengthwise so that it wraps the corner about 1⁄2 inch.

Hang the strip but peel it back from the corner a few inches.

Using a vertical guideline that’s about 1⁄8 inch farther from the corner than the narrowest width of the cutoff, apply the next drop on the adjacent wall, allowing it to wrap the corner.

After you smooth the second drop into place, trim it at the corner with a breakaway razor knife guided by a metal straightedge.

Toss the trimmed paper and peel the paper back from the corner enough to enable you to reposition the first drop.

With the first drop wrapping the corner and smoothed into place, smooth the second drop over the first.

Smooth the paper with a side-arm seam roller, which has no frame on one side of the roller so that you can get into corners with it.

Wallpapering outside corners

Outside corners present two problems. First, because they physically stand out, people often brush against or bang into them. And second, because outside corners stand out in the sense that they’re eye-catching, you want things in such a position to look as nice as possible. For these reasons, avoid placing a seam right at the corner where it may be brushed apart or may be more noticeable.

If the corner is perfectly plumb, you can just round it. If it’s out-of-plumb, you can use the wrap-and-overlap technique as described in the preceding, but with two differences.

Instead of wrapping the first drop about 1⁄2 inch (Step 1), wrap the corner at least 3 inches to ensure that it stays put.

Instead of having the second drop end right at the corner (Step 4), measure, cut, and position it so that it stops about 1⁄4 inch shy of the corner.

Both cuts are located by measurement and made on the cutting table, not in place.

Making cuts along the length of wallpaper is usually done with a special (read: expensive) 6-foot-long magnesium-alloy straightedge. As a substitute, you can use a 4-inch-wide strip of 1⁄4-inch plywood. If you don’t own a table saw, ask your lumber store to cut the plywood for you.

Cutting wallcovering dulls blades quickly. Snap off dull blades on a breakaway razor or change blades often on another type of cutter.